scholarly journals Some hematopoietic stem cells are more equal than others

2010 ◽  
Vol 207 (6) ◽  
pp. 1127-1130 ◽  
Author(s):  
Hanno Hock
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Hematopoietic Stem Cells ◽  
Hematologic Malignancies ◽  
Routine Clinical Practice ◽  
Malignant Cells ◽  
Hematopoietic Stem ◽  
Hematopoietic System ◽  
Continuous Progress ◽  
Basic Biology

Hematopoietic stem cells (HSCs) save lives in routine clinical practice every day, as they are the key element in transplantation-based therapies for hematologic malignancies. The success of clinical stem cell transplantation critically relies on the ability of stem cells to reconstitute the hematopoietic system for many decades after the administration of the powerful chemotherapy and/or irradiation that is required to eradicate malignant cells, but also irreversibly ablates patients’ own blood forming capacity. Surprisingly, despite enormous efforts and continuous progress in the field, our understanding of the basic biology of HSCs is still rather incomplete. Several recent studies substantially refine our understanding of the cells at the very top of the hematopoietic hierarchy, and suggest that we may need to revise the criteria we typically use to identify and define HSCs.

scholarly journals Clonal-level lineage commitment pathways of hematopoietic stem cells in vivo

2019 ◽  
Vol 116 (4) ◽  
pp. 1447-1456 ◽  
Author(s):  
Rong Lu ◽  
Agnieszka Czechowicz ◽  
Jun Seita ◽  
Du Jiang ◽  
Irving L. Weissman
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Hematopoietic Stem Cells ◽  
Hematopoietic Stem Cell ◽  
Lineage Commitment ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Hematopoietic System ◽  
Different Levels

While the aggregate differentiation of the hematopoietic stem cell (HSC) population has been extensively studied, little is known about the lineage commitment process of individual HSC clones. Here, we provide lineage commitment maps of HSC clones under homeostasis and after perturbations of the endogenous hematopoietic system. Under homeostasis, all donor-derived HSC clones regenerate blood homogeneously throughout all measured stages and lineages of hematopoiesis. In contrast, after the hematopoietic system has been perturbed by irradiation or by an antagonistic anti-ckit antibody, only a small fraction of donor-derived HSC clones differentiate. Some of these clones dominantly expand and exhibit lineage bias. We identified the cellular origins of clonal dominance and lineage bias and uncovered the lineage commitment pathways that lead HSC clones to different levels of self-renewal and blood production under various transplantation conditions. This study reveals surprising alterations in HSC fate decisions directed by conditioning and identifies the key hematopoiesis stages that may be manipulated to control blood production and balance.

A Review of Evaluating Hematopoietic Stem Cells Derived from Umbilical Cord Blood's Expansion and Homing

2020 ◽  
Vol 15 (3) ◽  
pp. 250-262
Author(s):  
Maryam Islami ◽  
Fatemeh Soleimanifar
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Umbilical Cord ◽  
Stromal Cells ◽  
Ex Vivo ◽  
Hematologic Malignancies ◽  
Future Directions ◽  
Hematopoietic Stem ◽  
Efficient Procedure ◽  
Hematopoietic Recovery

Transplantation of hematopoietic stem cells (HSCs) derived from umbilical cord blood (UCB) has been taken into account as a therapeutic approach in patients with hematologic malignancies. Unfortunately, there are limitations concerning HSC transplantation (HSCT), including (a) low contents of UCB-HSCs in a single unit of UCB and (b) defects in UCB-HSC homing to their niche. Therefore, delays are observed in hematopoietic and immunologic recovery and homing. Among numerous strategies proposed, ex vivo expansion of UCB-HSCs to enhance UCB-HSC dose without any differentiation into mature cells is known as an efficient procedure that is able to alter clinical treatments through adjusting transplantation-related results and making them available. Accordingly, culture type, cytokine combinations, O2 level, co-culture with mesenchymal stromal cells (MSCs), as well as gene manipulation of UCB-HSCs can have effects on their expansion and growth. Besides, defects in homing can be resolved by exposing UCB-HSCs to compounds aimed at improving homing. Fucosylation of HSCs before expansion, CXCR4-SDF-1 axis partnership and homing gene involvement are among strategies that all depend on efficiency, reasonable costs, and confirmation of clinical trials. In general, the present study reviewed factors improving the expansion and homing of UCB-HSCs aimed at advancing hematopoietic recovery and expansion in clinical applications and future directions.

scholarly journals Genetic control of the frequency of hematopoietic stem cells in mice: mapping of a candidate locus to chromosome 1.

1996 ◽  
Vol 183 (3) ◽  
pp. 1141-1150 ◽  
Author(s):  
C E Müller-Sieburg ◽  
R Riblet
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Hematopoietic Stem Cells ◽  
Inbred Strains ◽  
Cell Number ◽  
Chromosome 1 ◽  
Cell Frequency ◽  
Candidate Locus ◽  
Hematopoietic Stem ◽  
Differentiation And Proliferation

The genetic elements that govern the differentiation and proliferation of hematopoietic stem cells remain to be defined. We describe here marked strain-specific differences in the frequency of long-term culture-initiating cells (LTC-IC) in the bone marrow of different strains of mice. Mice of C57Bl/6 background showed the lowest levels of stem cells in marrow, averaging 2.4 +/- .06 LTC-IC/10(5) cells, BALB/c is intermediate (9.1 +/- 4.2/10(5) cells), and DBA/2 mice contained a 11-fold higher frequency of LTC-IC (28.1 +/- 16.5/10(5) cells) than C57Bl/6 mice. The genetic factors affecting the size of the stem cell pool were analyzed in the C57Bl/6 X DBA/2 recombinant inbred strains; LTC-IC frequencies ranged widely, indicating that stem cell frequencies are controlled by multiple genes. Quantitative trait linkage analysis suggested that two loci that have major quantitative effects are located on chromosome 1 near Adprp and Acrg, respectively. The mapping of the locus near Adprp was confirmed by finding an elevated stem cell frequency in B6.C-H25, a C57Bl/6 congenic strain that carries a portion of chromosome 1 derived from BALB/c mice. We have named this gene Scfr1 (stem cell frequency regulator 1). The allelic forms of this gene may be an important predictor of stem cell number and thus would be useful for evaluating cell sources in clinical stem cell transplantation.

scholarly journals Deletion of PI3-Kinase Promotes Myelodysplasia Through Dysregulation of Autophagy in Hematopoietic Stem Cells

2020 ◽  
Author(s):  
Kristina Ames ◽  
Imit Kaur ◽  
Yang Shi ◽  
Meng Tong ◽  
Taneisha Sinclair ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Myeloid Leukemia ◽  
Chromosomal Abnormalities ◽  
Akt Pathway ◽  
Hematopoietic Growth Factors ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Hematopoietic System ◽  
Phosphoinositide 3 Kinase

AbstractHematopoietic stem cells (HSCs) maintain the blood system through a delicate equilibrium between self-renewal and differentiation. Most hematopoietic growth factors and cytokines signal through phosphoinositide 3-kinase (PI3K) via three Class IA catalytic PI3K isoforms (P110α, β, and δ), encoded by Pik3ca, Pik3cb, and Pik3cd, respectively. The PI3K/AKT pathway is commonly activated in acute myeloid leukemia (AML), and PI3K is a common therapeutic target in cancer. However, it is not known whether PI3K is required for HSC differentiation or self-renewal. We previously demonstrated that individual PI3K isoforms are dispensable in HSCs1,2. To determine the redundant roles of PI3K isoforms in HSCs, we generated a triple knockout (TKO) mouse model with deletion of all three Class IA PI3K isoforms in the hematopoietic system. Surprisingly, we observed significant expansion of TKO HSCs after transplantation, with decreased differentiation capacity and impaired multilineage repopulation. Additionally, the bone marrow of TKO mice exhibited myelodysplastic features with chromosomal abnormalities. Interestingly, we found that macroautophagy (thereafter autophagy) is impaired in TKO HSCs, and that pharmacologic induction of autophagy improves their differentiation. Therefore, we have uncovered important roles for PI3K in autophagy regulation in HSCs to maintain the balance between self-renewal and differentiation.

scholarly journals CD34+ Hematopoietic Stem Cells Exert Accessory Function in Lipopolysaccharide-induced  T Cell Stimulation and CD80 Expression on Monocytes

1999 ◽  
Vol 189 (4) ◽  
pp. 693-700 ◽  
Author(s):  
Taila Mattern ◽  
Gundolf Girroleit ◽  
Hans-Dieter Flad ◽  
Ernst T. Rietschel ◽  
Artur J. Ulmer
Keyword(s):  
Stem Cells ◽  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Hematopoietic Stem Cells ◽  
Cell Stimulation ◽  
Hematopoietic Stem ◽  
Accessory Function ◽  
T Cell Stimulation ◽  
Blood Stem Cells

CD34+ hematopoietic stem cells, which circulate in peripheral blood with very low frequency, exert essential accessory function during lipopolysaccharide (LPS)-induced human T lymphocyte activation, resulting in interferon γ production and proliferation. In contrast, stimulation of T cells by “conventional” recall antigens is not controlled by blood stem cells. These conclusions are based on the observation that depletion of CD34+ blood stem cells results in a loss of LPS-induced T cell stimulation as well as reduced expression of CD80 antigen on monocytes. The addition of CD34-enriched blood stem cells resulted in a recovery of reactivity of T cells and monocytes to LPS. Blood stem cells could be replaced by the hematopoietic stem cell line KG-1a. These findings may be of relevance for high risk patients treated with stem cells or stem cell recruiting compounds and for patients suffering from endotoxin-mediated diseases.

Haploinsufficiency of AML1 results in a decrease in the number of LTR-HSCs while simultaneously inducing an increase in more mature progenitors

Blood ◽  
2004 ◽  
Vol 104 (12) ◽  
pp. 3565-3572 ◽  
Author(s):  
Weili Sun ◽  
James R. Downing
Keyword(s):  
Stem Cells ◽  
T Cells ◽  
Hematopoietic Stem Cells ◽  
Hematopoietic Stem ◽  
Hematopoietic System ◽  
Normal Limits ◽  
Platelet Disorder ◽  
Familial Platelet Disorder ◽  
Transcriptional Complex

The AML1/CBFβ transcriptional complex is essential for the formation of definitive hematopoietic stem cells (HSCs). Moreover, development of the hematopoietic system is exquisitely sensitive to the level of this complex. To investigate the effect of AML1 dosage on adult hematopoiesis, we compared the hematopoietic systems of AML1+/– and AML1+/+ mice. Surprisingly, loss of a single AML1 allele resulted in a 50% reduction in long-term repopulating hematopoietic stem cells (LTR-HSCs). This decrease did not, however, extend to the next level of hematopoietic differentiation. Instead, AML1+/– mice had an increase in multilineage progenitors, an expansion that resulted in enhanced engraftment following transplantation. The expanded pool of AML1+/– progenitors remained responsive to homeostatic mechanisms and thus the number of mature cells in most lineages remained within normal limits. Two notable exceptions were a decrease in CD4+ T cells, leading to an inversion of the CD4+ to CD8+ T-cell ratio and a decrease in circulating platelets. These data demonstrate a dosage-dependent role for AML1/CBFβ in regulating the quantity of HSCs and their downstream committed progenitors, as well as a more restricted role in T cells and platelets. The latter defect mimics one of the key abnormalities in human patients with the familial platelet disorder resulting from AML1 haploinsufficiency.

Stem Cell Defect in Ubiquitin-Green Fluorescent Protein Mice Facilitates Engraftment of Lymphoid-Primed Hematopoietic Stem Cells

Stem Cells ◽  
2018 ◽  
Vol 36 (8) ◽  
pp. 1237-1248
Author(s):  
Kateřina Faltusová ◽  
Katarína Szikszai ◽  
Martin Molík ◽  
Jana Linhartová ◽  
Petr Páral ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Green Fluorescent Protein ◽  
Hematopoietic Stem Cells ◽  
Fluorescent Protein ◽  
Hematopoietic Stem ◽  
Green Fluorescent ◽  
Cell Defect

The Ethics of Embrionic Stem Cells Research

2019 ◽  
pp. 244-263
Author(s):  
Alexandra Huidu
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Hematopoietic Stem Cells ◽  
Embryonic Stem Cell ◽  
Stem Cell Research ◽  
Embryonic Stem ◽  
Modern Medicine ◽  
Embryonic Stem Cell Research ◽  
Hematopoietic Stem ◽  
Research Fields

Embrionic stem cells research, as opposed to hematopoietic stem cells research, has always stirred up many controversies of ethical nature that have projected their effects in the specialized doctrine of the domain of medical bioethics and law. Some of these controversies have been transposed at the legislative level (both by international normative acts and by the national laws of the states) while others are not yet de object of consensus. All that is not transposed by law remains in the exclusive sphere of ethics, so the ethical discussion in embryonic stem cell research is not only relevant for today's modern medicine but also of the utmost importance for a category of specialists in various research fields.

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